In TD-SCDMA (Time Division-Synchronous Code Division Multiple Access), LTE (Long Term Evolution) and other communication systems, the uplink shared channel refers to an uplink transmission channel shareable among several UE (User Equipment).
The uplink shared channel resource in a communication system is allocated usually by the following methods: first acquiring a channel quality indication, then looking up the mapping table of the channel quality indication and a resource number by use of the channel quality indication, to search a resource number capable of satisfying the volume of data-to-be-transmitted of user as the basis for subsequent allocation of resources.
Take LTE system as an example. The shared channel resources are all allocated at base station. UE sends an uplink Sounding reference symbol; then the base station detects and converts this reference symbol and characterizes the uplink shared channel quality indication through MCS (Modulation Coding Scheme). After acquiring the channel quality indication, the base station searches a resource profile capable of satisfying the volume of data-to-be-transmitted of user by looking up TB_size table and uses this resource profile as a resource allocation result. Wherein, the TB_size table is the mapping table of the channel quality indication and the resource number, which is shown in Table 1; the resource profile is indicated by MCS level and PRB number; PRB refers to physical resource block (Physical Resource Block), used to describe the actual physical resource allocation; PRB number is the resource number mentioned above.
For example, Table 1 is TB_size table with LTE standard definition, which lists the tables in a system bandwidth of 1.4 MHz. The column ITBS in Table 1 corresponds to the channel quality indication MCS, with the value ranging from 0 to 26; the row NPRB corresponds to the occupied PRB number, with the value ranging from 1 to 110, and ranging from 1 to 6 when the bandwidth is 1.4 MHz; the data in the table indicate the data volume tb_size able to carry by the corresponding resource profile (MCS level, PRB number). When the bandwidth is 1.4 MHz, for an uplink shared channel, the base station acquires the wideband channel quality indication MCSwideband=3 by measuring the uplink Sounding reference symbol sent the UE1 and the volume of data-to-be-transmitted of UE1 UE1data=200 bits. By looking up the fourth row (MCS=3 row) of Table 1, we can know the data volume able to carry by the resource profile (MCS=3, PRB_NUM=4) is 208 bits upon NPRB=4, which is greater than the volume of data-to-be-transmitted of the UE1 (200 bits), therefore, the resource profile (MCS=3, PRB_NUM=4) can be used as a basis for resource allocation and the specific location of the allocated resource shall be further determined. Finally, the MCS level and the location of the allocated resource are transmitted to UE1 via a control channel; UE1 transmits uplink data in the specified resource location as per designated MCS.
TABLE 1 TB_size Table [B = 1.4 MHz] with LTE Standard DefinitionNPRBITBS12345601632568812015212456881441762082327214417620825634010417620825632845612020825632840857214422432842450463281762563925046007104224328472584712812025639253668080891362964566167769361014432850468087210321117637658477610001192122084406809041128135213224488744100012561544142565528401128141617361528060090412241544180016328632968128816081928173366961064141618002152183767761160154419922344194088401288173621522600204409041384186423442792214881000148019922472298422520106416082152266432402355211281736228028563496245841192180024082984362425616125618642536311237522671214802216298437524392
The above method for allocating uplink channel resource can satisfy the resource allocation of the volume of data-to-be-transmitted of user under normal circumstances, but in some cases, it may cause too much interference, reducing the overall performance of the system.